1. Field of the Invention
This invention relates to a vacuum suction cup, especially for a windshield of a mechanical vehicle, provided with an elastic suction cup with a spindle protruding axially therefrom. The spindle slides axially within a guiding bushing of a dome which shields the suction cup from outside.
2. Description of the Related Art
An automotive and other mechanical vehicles equipment market experiences currently tremendous growth in a number of a diverse electronic equipment, e.g. navigation devices, mobile phones, TV screens and others, as supplementary devices installed in mechanical vehicles. Such equipment is commonly attached by various holders and brackets as well as vacuum suction cups onto a windshield of the mechanical vehicle. Thus several new designs of vacuum suction cups have been released recently to the market. They are both to provide reliable connection of a bracket with the windshield, and, on the other hand, they are to be easily fastened and unfastened from the windshield of the vehicle.
European patent EP 133808 describes a vacuum suction cup connected to a holder, composed of elastic concave suction cup, which circumference adheres to a flat and smooth surface, e.g. a glass pane. The suction cup has a threaded pin protruding from its external surface. The suction cup is covered by an intermediate member in the form of a dish or dome, which adjoins the cup around the circumference. The dome has a threaded hole which is fastened to the threaded pin of the suction cup. Once tightened, the dome covers the suction cup over its circumference completely. The dome is provided with protruding axial pin terminated with a flange for suspending an object. Once the suction cup is pressed against the pane surface, where the suction cup is to be fixed, one fastens the dome over the protruding threaded pin, which generates a vacuum between the pane and the suction cup, which in turn fastens the suction cup to the smooth surface of the pane. To unfasten the vacuum suction cup from the pane, one has to tighten the dome more over the threaded pin of the suction cup, which in turn makes it to tear off the flat and smooth pane.
British patent GB 2420147A relates to a vacuum suction cup provided with an elastic suction cup, which once pressed, fastens reliably on a flat and smooth surface, e.g. a pane. There is a pin with a threaded hole, protruding outwards and located in a central thickened area of the suction cup. There is a suction cup covering dome fitted with a threaded spindle pointing downwards, located directly on the suction cup. The threaded spindle in the covering dome fastens to the threaded hole in the pin of the suction cup. To facilitate gripping of the dome at fastening, butterfly type grips are found on the external surface. A pin protruding from the dome is used for suspending an object.
Once the suction cup is pressed against a pane, the suction cup flattens and the pin fastening of the dome to the suction cup makes it to rise, which generates under pressure in the zone between the suction cup and the pane, which in turn fastens the suction cup to the pane. The suction cup clings to the pane over entire circumference, so even loads applied eccentrically by an object suspended on the pin do not make it to tear off the flat and smooth surface of the pane. To unfasten the vacuum suction cup, one has to loosen the dome to make the suction cup to adhere to the pane over entire area, and to loosen the suction cup.
German utility model DE 202004010999U1 describes a stand or hanger provided with a vacuum suction cup connected by means of an elastic metal tube in plastic shielding with a holder for hanging an object on. The elastic concave suction cup has a threaded pin to fasten a nut to. A dome is attached to the lower surface of the nut. The dome with its circumference rests on the outer surface of the suction cup. The elastic tube on the suction cup side terminates with a clamp, which, as its internal depressions match with the nut sides, makes the nut to turn when turning the elastic tube. When the suction cup is applied to a flat and smooth surface, e.g. a pane, after few turns of the flexible tube the nut causes the pin in the suction cup to go off the flat and smooth surface of the pane, which generates under pressure keeping the suction cup in place. Then a suitable object can be placed on the stand or hanger attached to the suction cup.
All known designs of suction cups are of marked inconvenience, as the suction cup pin moves along its axis due to external or internal thread, it is necessary to complete one or more full turns of the dome which threaded hole with the threaded pin is fastened to, in order to move the spindle by a distance required to attach the suction cup reliably. In order to eliminate this inconvenience, there are suction cups released to the market recently, where the spindle protruding from the suction cup is provided with guiding pins, moving along the suction cup axis by one-arm handle rotating freely within the suction cup.
European patent EP 1457690 discloses a stand or hanger provided with a vacuum suction cup on one side and a handle to suspend an object on the other side. Both parts are connected by a flexible bar covered by a plastic shielding, which allows one to attach an object in any place and position relative to a flat and smooth surface, e.g. a windshield of a mechanical vehicle. The suction cup is provided with a protruding spindle, formed integrally with the flexible bar. The suction cup spindle has a transverse hole, where a pin protrudes from. There is also an axial hole containing a helical spring, which presses the suction cup against the windshield. A pin passes through the transverse hole in the suction cup, through longitudinal holes formed in walls of a suction cup support as well as through an axial hole in a single arm lever. The lever rotates around the pin, while supported on its cam surface by the external surface of the support. As the lever rises, it loads the spring and makes the suction cup to go off the flat and smooth pane surface and generates a vacuum between the suction cup and the pane. The vacuum keeps the suction cup in place firmly.
German utility model DE 202005014289U1 relates to a bracket with a vacuum suction cup for mounting on a flat and smooth surface, e.g. wall or pane. The suction cup of the bracket comprises an elastic suction cup, which adheres with its entire circumference to the flat and smooth surface, e.g. a pane, and a round dome covering the suction cup with its entire circumference. The bracket for hanging an object protrudes from the dome, and it is provided with hollow joints, which makes possible to attach any object in any convenient angular position. There is a sliding pin in longitudinal holes on sides of the bracket, which passes through a spindle protruding from the suction cup. There is also a helical spring above the spindle, which pushes the suction cup off the internal surface of the dome. A pin located in the spindle of the suction cup engages with elongated holes in walls of the bracket and with one-arm angular lever. The lever is provided with a cam surface resting on the external surface of the dome. When the lever is in its risen position it releases the helical spring, which presses the suction cup against the flat and smooth surface of the pane or wall. In a depressed position the lever compresses the spring, and, through the pin, makes the spindle of the suction cup to rise and generate vacuum below it and the flat and smooth surface of the pane.
Placing both the pin and slit in the dome outside the suction cup is the main inconvenience of both designs, as both parts might be easily broken. Moreover, such suction cups are inconvenient in operation as in order to attach it, it is necessary to press the suction cup against the pane with one hand, and at the same time to turn the lever by the other hand.